This research aims at evaluating the performance of a combined system of biochar gasification and a sorption-enhanced water–gas shift reaction (SEWGS) for synthesis gas production. The effects of mangrove-derived biochar gasification temperature, pattern of combined gasification and SEWGS, amount of steam and CO₂ added as gasifying agent, and SEWGS temperature were studied in this work. The performances of the combined process were examined in terms of biochar conversion, gaseous product composition, and CO₂ emission. The results revealed that the hybrid SEWGS using one-body multi-functional material offered a greater amount of H₂ with a similar amount of CO₂ emissions when compared with separated sorbent/catalyst material. The gasification temperature of 900 °C provided the highest biochar conversion of ca. 98.7%. Synthesis gas production was found to depend upon the amount of water and CO₂ added and SEWGS temperature. Higher amounts of H₂ were observed when increasing the amount of water and the temperature of the SEWGS system.